The present invention relates to devices for making repetitive stamping operations on a workpiece and, more particularly, to devices for stamping notches in stator laminations.
Typically, large electric motors include a stator core which is composed of a stack of relatively thin, circular laminations made of metal such as copper. Grooves are formed in the core of the stator by notching teeth-like slots on each of the laminations which are aligned when the laminations are arranged in a stack. Coils or rods formed from several insulated wires (windings) are secured in such slots. The slots are typically formed by placing pre-notched stator laminations, which have a central opening already formed therein, over a spindle or hub on a turntable which indexes the laminations between a die set which forms the notches. An example of such a stator lamination is disclosed in copending application Ser. No. 08/369,097, filed Jan. 5, 1995 (Attorney Docket 533809-026), the disclosure of which is incorporated herein by reference.
A disadvantage of such a prior art system is that it lacked means for positively securing the pre-notched laminations to the turntable, and for automatically removing the finished laminations from the spindle of the turntable. Further, while such progressive stamping devices are less expensive than devices for notching the entire lamination at once, they are less accurate since the lamination must be indexed as the notching procedure is performed.
Accordingly, there is a need for a stator lamination jig system which facilitates the mounting of the pre-notched lamination on the turntable, and the removal of the finished, notched lamination from the turntable. Further, there is a need for a stator lamination jig system which securely holds the lamination during the notching process without manual assistance.